US695264A - Process of manufacturing steel. - Google Patents

Description

llnrrnn SrA'rns ATENT Fries,

AND THOMAS KERRISON BELLIS, OF ENGLAND.

PROCESS OF MANUFACTURING STEEL.

SPECIFICATION forming part of Letters Patent No. 695,264, dated March 11, 1902.

Application filed December 13, 1900. Serial No. 39,781. (No specimens.)

To all whom it may concern.-

Be it known that we, THOMAS ANDREW, residing at Richmond, and THOMAS KERRISON BELLIS, residing at London, England, subjects of the Queen of Great Britain, have invented certain new and useful Improvements in an Improved Manufacture of High-Grade Steel from Low-Grade Steel, of which the following is a specification.

This invention consists in a process for the treatment of either Bessemer or open-hearth steels, whereby the same may be cheaply and efficiently converted into steel havinga crystalline fracture of absolute regularity and fineness and possessing the well-known qualities of steel produced by cementation, subsequent melting in crucibles and casting, and commonly known as crucible steel.

The salient feature of our process is the use of hydrogen as an element that will impart to the product of the Bessemer and openhearth processes the qualities wanted. The aflinity of this gas for metals is well known, and it appears that iron especially naturally contains it in greater or less quantity. It is our belief that one of the prime reasons why Bessemer and open-hearth steels havenot the high quality of crucible steel is that in the process of manufacture much of their hydrogen is lost. We are convinced of this by the following conside1'ationsviz., first, because since the heating of steel up to the molten condition means the forcing out of its gases,while cooling it means, at least up to a certain point oftemperature, the reabsorption of gases, it is not an undue extravagance to assume that even the hydrogen which remains after the metal has been put through extreme heats in process of manufacture would in the Bessemer and openhearth processes be attacked and burned by the atmospheric oxygen to which those processes permit it to be exposed and which it tends to absorb during the cooling stage, (thus incidentally accounting in a measure for the phenomenon known as recalescence or that condition in the cooling metal where recurs a temporary glowing;) second, because experiments by Prof. Arnold and others show that bubbles formed in openhearth and Bessemer steels are often bubbles of hydrogen, and, third, because the very salutary results which we and others of high reputation as experts in the art of steel-making have obtained in practicing our process aiford an incontrovertible substantiation of the accuracy of our deductions. It became our object, therefore, to treat Bessemer and open-hearth steels with a view to recharging them with the lost hydrogen, and so imparting to them the superior quality of steels made after the more cumbersome and tedious crucible process-a process wherein at least no such undesirable combining of the hydrogen (and also the carbon for that matter) of the metal with atmospheric oxygen as is above referred to is permitted and Where the loss of hydrogen, if any, is inappreciable.

process we first heat Bessemer or open-hearth bars or billets in an ordinary closed air-fur:

open the pores or grain of the metal and being, it may be noted, slightly greater than that of the recalescent point. The billets sand floor, and at once covered with a suitable bonnet, into which is injected a jet of pure hydrogen. By contact with the metal the haustion of what air is in itially inclosed in the bonnet with the billets. When the air is combath of pure hydrogen gas, which it freely absorbs. The metal may remain exposed to the gas for, say, fifteen minutes, though longer, if desired. hen the metal cools, the hydrogen is not only retained mechanicpores or grain of the metal, but chemically, for the hydrogen absorbed has combined with the carbon of the metal. At this stage,there- To this end, therefore, in carrying out our nace, subjecting them to a good soaking heatt. e., a heat sufficient to appreciably when at a bright-red heat-t'. e., when their grain is appreciably opened-are quickly withdrawn, laid on a suitable support on a gas will be ignited, serving to effect the expletely exhausted, the metal remains in a ally in combination by the closing of the drogen; but the union thus effected has not caused the quality of the steel to be improved, though the hydrogen is established in the composition With adequate tenacity, it requiring a melting heat to bring about its separation from the metal after being once incorporated therein. The carbon, which is a fugitive element, under reheatings and temperings is neither fixed nor crystallized consistent with the superior quality which the product isintended to possess. To quite perfectly fix and crystallize the carbon, therefore, the steel is next chilled. This is effected by first heating the billets (Whether or not they have meantime cooled is not abso lutely essential) to a White heat, it they are of low carbon, (.10 per cent. or .15 per cent,) or to simply a red heat, if they have above that percentage of carbon, (and to avoid danger of fracture when chilled their carbon should not be over .85 per cent,) and then cooling them in any suitable and well-known chilling-bath which does not evolve oxygen, oxygen having, as is Well recognized in this art, a deleterious elfect on the steel. Such baths are common and none of them needs to a proper understanding of this process to be set forth herein.

It should be remarked that by preference the billets are formed not smaller than three or four inches square. It is well known that a perfect and homogeneous crystallization is best secured by great pressure acting supplementary or auxiliarially to the effects of heat, and this We secure by not making the billets too large, so that when they are subjected to the chill the precipitous contractingand molecular tension which results in the outer shell of each billet coacts with the as yet still heated and resisting inner part thereof to effectan unusual state of hardness in said outer shell.

Having thus fully described our invention, what we claim as new, and desire to secure byvLetters Patent, is

The process of treating steel Which consists in first opening, by the application of heat, the pores or grain of the steel to appreciably expose the carbon of the same; secondly, subjecting said steel, with its pores open and its carbon exposed, to a bath of hydrogen; and, thirdly, finally raising the temof heat, and immediately chilling the same precipitously to fix the carbon, substantially as described.

In testimony whereof we have hereunto set our hands in presence of two subscribing witnesses.

THOMAS ANDREW. THOMAS KERRISON BELLIS. Witnesses:

HERBERT STEWART, ERNST LAFFERTY.

- perature of the steel, bya second application